Rolling lines with mill stands which are located at fixed locations along the mill line but can be replaced or exchanged are utilized in the continuous rolling of strand-shaped workpieces, like rod and wire, have been provided heretofore for the rolling of semimanufactured workpieces, i.e. workpieces which require finished rolling or other modifications to be turned into finished products, for rod, bar steel, for rod-shaped or bar-shaped structural shapes or sections for wire. They can be operated more or less continuously and the line can be a straight line or provided with diverters or the like which can loop the workpiece, divert the workpiece between branches of the line or otherwise modify the path of the workpiece through the mill stands or rolls. For a dimension change, the stands may be shifted out of the fixed position along the line and replaced in their position by another stand, previously formed for this purpose and set to the dimensions of the new product.
For the back and forth displacement of the mill stand into and out of position, additional units are required and there have been a number of proposals for achieving that result. In DE 33 17 748, for example, there are vertical and horizontal mills disposed alternately and in succession along the rolling lien and rolled product guides between the rolls of neighboring mill stands. The replacement of a roll set is achieved by shifting the entire mill group on a holding frame out of the roll line into a replacement position and then each mill frame out of the replacement position relative to the holder frame by means of a drive transverse to the roll line. The mill stands are then disposed laterally of these roll positions. The vertical frames are mounted on the holder frames in the shifting device so as to be displaceable transverse to the rolling line. For each mill in the roll replacement position a turntable is provided as well as a carriage which is displaceable at an inclination to the shifting direction. Apart from this expensive approach to the roll replacement devices, it is not possible with present day units to effect a roll replacement in very short times as is desirable.
In another proposal the mill rolls are replaced in cassettes via guide rails and actuators which operate transversely to the rolling line. These systems require the withdrawal of the roll that was previously used before it can be replaced by the roll set in readiness so that the time required for the roll replacement is significant.